This invention relates generally to a torquing device. More particularly, this invention relates to an improved torquing device commonly called a power torque wrench which is pneumatically or hydraulically powered.
Powered wrenches for turning threaded connection members such as nuts and bolts are well known in the art. Such powered wrenches typically employ a ratchet mechanism which acts on a socket member which is suitably sized to turn a selected nut or bolt. It will be appreciated that power wrenches have a generally complex structure and are relatively large and bulky. As a consequence, it is difficult to utilize prior art powered wrenches in cramped or hard to reach places.
Many prior art power wrenches include a reaction unit or anchor adapter which attaches to a nut or bolt spaced from the actual nut or bolt which is being turned. Examples of such prior art power wrenches include U.S. Pat. Nos. 4,027,560; 4,132,136; 4,308,767; and 4,429,597. These power wrenches are adapted for driving a plurality of adjacently spaced members. The wrenches typically include a power cylinder and piston arrangement with a reaction or anchor assembly and a wrench assembly connected to the cylinder and/or piston.
As already mentioned, many of the prior art power wrenches are bulky and cumbersome and are therefore unable to access nuts or bolts in hard to reach places. Another disadvantage of these wrenches is that the reaction system usually involves loading in compression. It will be appreciated that constant compression on the reaction assembly may lead to problems relating to excessive bending stress and/or column strength. Another disadvantage with prior art power wrenches of the type discussed hereinabove is that such units are required to match a different socket member to each size of nut or bolt to be turned. Consequently, the power wrench operator must purchase and stock a collection of relatively large, heavy and expensive socket heads (one for each size nut). This leads to increased costs as well as the cumbersome necessity of supplying each field operator with a plurality of heavy sockets. Still another problem with prior art wrenches is the often times uneven driving force and loading exerted by the driving pawl on a nut or bolt during successive power strokes. Another problem exists with prior art wrenches in which the driver and driven parts are offset. Such wrenches, if they do not have a main housing, must have two reaction points, one for force and one for torque. Thus, such wrenches are either large, bulky and heavy (because of the main housing); or they must have two reaction points.